Inviting a new user

[MuhammadKhalilzadeh]

We need to implement the feature of inviting new users to the dashboard based on their Emails.

Now the thing is if a user is invited, he/she will be able to register from User Register page as followed, which has no email input:

So, we may proceed with one of the followings:

1. When we invited someone. their email is stored, and a link will be sent to them, via that link they will be able to register. (Then we'll need an email messaging service)
2. We can add email field here as well, but the way it works that email field will only check if the email is for someone who is invited.
3. Once we invite someone, we can generate a code for them, like an invitation code. Once invited, they can enter their code (in a new input added) and then proceed.

@gorkemcetin
What do you think?
Any other suggestions you may have?